The present invention relates to an angle-measuring instrument which includes two arms, which are interconnected in such a way that they can be pivoted about a common shaft, and an indicator for the angle of spread of the two arms.
Known angle-measuring instruments are pivoted with a scale which surrounds the common axis in the manner of a circular ring. The angle of spread obtained between the arms can be read off on the calibration of the scale. The diameter of this scale is relatively small, as a result of which the distance between lines on the scale is so small that only a relatively approximate reading is possible.
With another known embodiment of an angle-measuring instrument, those ends of the two arms which are remote from the shaft are connected to one another by means of a tape measure, which is rigidly mounted to one of the arms and can be wound up in the other arm on a spring-loaded reel. When the angle-measuring instrument is spread apart, the tape measure is unwound, with the unwound length thereof being relied upon for determination of the angle. However, a drawback to this heretofore known instrument is that the connection of the two ends of the arms formed by the measuring tape often hinders the measuring process.
It is an object of the present invention to provide a convenient angle-measuring instrument with which, without difficulty and without disrupting attachments, outer and inner angles of parts not only can be precisely measured, but also can be indicated in such a way that such angles can be read off easily.